/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/**
 * @file
 * Dynamic pool memory manager
 *
 * lwIP has dedicated pools for many structures (netconn, protocol control blocks,
 * packet buffers, ...). All these pools are managed here.
 */

#include <net/lwip/opt.h>

#include <net/lwip/memp.h>
#include <net/lwip/pbuf.h>
#include <net/lwip/udp.h>
#include <net/lwip/raw.h>
#include <net/lwip/tcp_impl.h>
#include <net/lwip/ipv4/igmp.h>
#include <net/lwip/api.h>
#include <net/lwip/api_msg.h>
#include <net/lwip/tcpip.h>
#include <net/lwip/sys.h>
#include <net/lwip/timers.h>
#include <net/lwip/stats.h>
#include <net/lwip/netif/etharp.h>
#include <net/lwip/ipv4/ip_frag.h>
#include <net/lwip/snmp_structs.h>
#include <net/lwip/snmp_msg.h>
#include <net/lwip/netif/ppp_oe.h>

#include <string.h>

#if !MEMP_MEM_MALLOC			/* don't build if not configured for use in lwipopts.h */

struct memp {
	struct memp *next;
#if MEMP_OVERFLOW_CHECK
	const char *file;
	int line;
#endif							/* MEMP_OVERFLOW_CHECK */
};

#if MEMP_OVERFLOW_CHECK
/* if MEMP_OVERFLOW_CHECK is turned on, we reserve some bytes at the beginning
 * and at the end of each element, initialize them as 0xcd and check
 * them later. */
/* If MEMP_OVERFLOW_CHECK is >= 2, on every call to memp_malloc or memp_free,
 * every single element in each pool is checked!
 * This is VERY SLOW but also very helpful. */
/* MEMP_SANITY_REGION_BEFORE and MEMP_SANITY_REGION_AFTER can be overridden in
 * lwipopts.h to change the amount reserved for checking. */
#ifndef MEMP_SANITY_REGION_BEFORE
#define MEMP_SANITY_REGION_BEFORE  16
#endif							/* MEMP_SANITY_REGION_BEFORE */
#if MEMP_SANITY_REGION_BEFORE > 0
#define MEMP_SANITY_REGION_BEFORE_ALIGNED    LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_BEFORE)
#else
#define MEMP_SANITY_REGION_BEFORE_ALIGNED    0
#endif							/* MEMP_SANITY_REGION_BEFORE */
#ifndef MEMP_SANITY_REGION_AFTER
#define MEMP_SANITY_REGION_AFTER   16
#endif							/* MEMP_SANITY_REGION_AFTER */
#if MEMP_SANITY_REGION_AFTER > 0
#define MEMP_SANITY_REGION_AFTER_ALIGNED     LWIP_MEM_ALIGN_SIZE(MEMP_SANITY_REGION_AFTER)
#else
#define MEMP_SANITY_REGION_AFTER_ALIGNED     0
#endif							/* MEMP_SANITY_REGION_AFTER */

/* MEMP_SIZE: save space for struct memp and for sanity check */
#define MEMP_SIZE          (LWIP_MEM_ALIGN_SIZE(sizeof(struct memp)) + MEMP_SANITY_REGION_BEFORE_ALIGNED)
#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x) + MEMP_SANITY_REGION_AFTER_ALIGNED)

#else							/* MEMP_OVERFLOW_CHECK */

/* No sanity checks
 * We don't need to preserve the struct memp while not allocated, so we
 * can save a little space and set MEMP_SIZE to 0.
 */
#define MEMP_SIZE           0
#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x))

#endif							/* MEMP_OVERFLOW_CHECK */

/** This array holds the first free element of each pool.
 *  Elements form a linked list. */
static struct memp *memp_tab[MEMP_MAX];

#else							/* MEMP_MEM_MALLOC */

#define MEMP_ALIGN_SIZE(x) (LWIP_MEM_ALIGN_SIZE(x))

#endif							/* MEMP_MEM_MALLOC */

/** This array holds the element sizes of each pool. */
#if !MEM_USE_POOLS && !MEMP_MEM_MALLOC
static
#endif
const u16_t memp_sizes[MEMP_MAX] = {
#define LWIP_MEMPOOL(name, num, size, desc)  LWIP_MEM_ALIGN_SIZE(size),
#include <net/lwip/memp_std.h>
};

#if !MEMP_MEM_MALLOC			/* don't build if not configured for use in lwipopts.h */

/** This array holds the number of elements in each pool. */
static const u16_t memp_num[MEMP_MAX] = {
#define LWIP_MEMPOOL(name, num, size, desc)  (num),
#include <net/lwip/memp_std.h>
};

/** This array holds a textual description of each pool. */
#ifdef LWIP_DEBUG
static const char *memp_desc[MEMP_MAX] = {
#define LWIP_MEMPOOL(name, num, size, desc)  (desc),
#include <net/lwip/memp_std.h>
};
#endif							/* LWIP_DEBUG */

#if MEMP_SEPARATE_POOLS

/** This creates each memory pool. These are named memp_memory_XXX_base (where
 * XXX is the name of the pool defined in memp_std.h).
 * To relocate a pool, declare it as extern in cc.h. Example for GCC:
 *   extern u8_t __attribute__((section(".onchip_mem"))) memp_memory_UDP_PCB_base[];
 */
#define LWIP_MEMPOOL(name, num, size, desc) u8_t memp_memory_ ## name ## _base \
	[((num) * (MEMP_SIZE + MEMP_ALIGN_SIZE(size)))];
#include <net/lwip/memp_std.h>

/** This array holds the base of each memory pool. */
static u8_t *const memp_bases[] = {
#define LWIP_MEMPOOL(name, num, size, desc) memp_memory_ ## name ## _base,
#include <net/lwip/memp_std.h>
};

#else							/* MEMP_SEPARATE_POOLS */

/** This is the actual memory used by the pools (all pools in one big block). */
static u8_t memp_memory[MEM_ALIGNMENT - 1
#define LWIP_MEMPOOL(name, num, size, desc) + ((num) * (MEMP_SIZE + MEMP_ALIGN_SIZE(size)))
#include <net/lwip/memp_std.h>
];

#endif							/* MEMP_SEPARATE_POOLS */

#if MEMP_SANITY_CHECK
/**
 * Check that memp-lists don't form a circle, using "Floyd's cycle-finding algorithm".
 */
static int memp_sanity(void)
{
	s16_t i;
	struct memp *t, *h;

	for (i = 0; i < MEMP_MAX; i++) {
		t = memp_tab[i];
		if (t != NULL) {
			for (h = t->next; (t != NULL) && (h != NULL); t = t->next, h = (((h->next != NULL) && (h->next->next != NULL)) ? h->next->next : NULL)) {
				if (t == h) {
					return 0;
				}
			}
		}
	}
	return 1;
}
#endif							/* MEMP_SANITY_CHECK */
#if MEMP_OVERFLOW_CHECK
#if defined(LWIP_DEBUG) && MEMP_STATS
static const char *memp_overflow_names[] = {
#define LWIP_MEMPOOL(name, num, size, desc) "/"desc,
#include <net/lwip/memp_std.h>
};
#endif

/**
 * Check if a memp element was victim of an overflow
 * (e.g. the restricted area after it has been altered)
 *
 * @param p the memp element to check
 * @param memp_type the pool p comes from
 */
static void memp_overflow_check_element_overflow(struct memp *p, u16_t memp_type)
{
	u16_t k;
	u8_t *m;
#if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
	m = (u8_t *)p + MEMP_SIZE + memp_sizes[memp_type];
	for (k = 0; k < MEMP_SANITY_REGION_AFTER_ALIGNED; k++) {
		if (m[k] != 0xcd) {
			char errstr[128] = "detected memp overflow in pool ";
			char digit[] = "0";
			if (memp_type >= 10) {
				digit[0] = '0' + (memp_type / 10);
				strcat(errstr, digit);
			}
			digit[0] = '0' + (memp_type % 10);
			strcat(errstr, digit);
#if defined(LWIP_DEBUG) && MEMP_STATS
			strcat(errstr, memp_overflow_names[memp_type]);
#endif
			LWIP_ASSERT(errstr, 0);
		}
	}
#endif
}

/**
 * Check if a memp element was victim of an underflow
 * (e.g. the restricted area before it has been altered)
 *
 * @param p the memp element to check
 * @param memp_type the pool p comes from
 */
static void memp_overflow_check_element_underflow(struct memp *p, u16_t memp_type)
{
	u16_t k;
	u8_t *m;
#if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
	m = (u8_t *)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
	for (k = 0; k < MEMP_SANITY_REGION_BEFORE_ALIGNED; k++) {
		if (m[k] != 0xcd) {
			char errstr[128] = "detected memp underflow in pool ";
			char digit[] = "0";
			if (memp_type >= 10) {
				digit[0] = '0' + (memp_type / 10);
				strcat(errstr, digit);
			}
			digit[0] = '0' + (memp_type % 10);
			strcat(errstr, digit);
#if defined(LWIP_DEBUG) && MEMP_STATS
			strcat(errstr, memp_overflow_names[memp_type]);
#endif
			LWIP_ASSERT(errstr, 0);
		}
	}
#endif
}

/**
 * Do an overflow check for all elements in every pool.
 *
 * @see memp_overflow_check_element for a description of the check
 */
static void memp_overflow_check_all(void)
{
	u16_t i, j;
	struct memp *p;

	p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
	for (i = 0; i < MEMP_MAX; ++i) {
		p = p;
		for (j = 0; j < memp_num[i]; ++j) {
			memp_overflow_check_element_overflow(p, i);
			p = (struct memp *)((u8_t *)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
		}
	}
	p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
	for (i = 0; i < MEMP_MAX; ++i) {
		p = p;
		for (j = 0; j < memp_num[i]; ++j) {
			memp_overflow_check_element_underflow(p, i);
			p = (struct memp *)((u8_t *)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
		}
	}
}

/**
 * Initialize the restricted areas of all memp elements in every pool.
 */
static void memp_overflow_init(void)
{
	u16_t i, j;
	struct memp *p;
	u8_t *m;

	p = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
	for (i = 0; i < MEMP_MAX; ++i) {
		p = p;
		for (j = 0; j < memp_num[i]; ++j) {
#if MEMP_SANITY_REGION_BEFORE_ALIGNED > 0
			m = (u8_t *)p + MEMP_SIZE - MEMP_SANITY_REGION_BEFORE_ALIGNED;
			memset(m, 0xcd, MEMP_SANITY_REGION_BEFORE_ALIGNED);
#endif
#if MEMP_SANITY_REGION_AFTER_ALIGNED > 0
			m = (u8_t *)p + MEMP_SIZE + memp_sizes[i];
			memset(m, 0xcd, MEMP_SANITY_REGION_AFTER_ALIGNED);
#endif
			p = (struct memp *)((u8_t *)p + MEMP_SIZE + memp_sizes[i] + MEMP_SANITY_REGION_AFTER_ALIGNED);
		}
	}
}
#endif							/* MEMP_OVERFLOW_CHECK */

/**
 * Initialize this module.
 *
 * Carves out memp_memory into linked lists for each pool-type.
 */
void memp_init(void)
{
	struct memp *memp;
	u16_t i, j;

	for (i = 0; i < MEMP_MAX; ++i) {
		MEMP_STATS_AVAIL(used, i, 0);
		MEMP_STATS_AVAIL(max, i, 0);
		MEMP_STATS_AVAIL(err, i, 0);
		MEMP_STATS_AVAIL(avail, i, memp_num[i]);
	}

#if !MEMP_SEPARATE_POOLS
	memp = (struct memp *)LWIP_MEM_ALIGN(memp_memory);
#endif							/* !MEMP_SEPARATE_POOLS */
	/* for every pool: */
	for (i = 0; i < MEMP_MAX; ++i) {
		memp_tab[i] = NULL;
#if MEMP_SEPARATE_POOLS
		memp = (struct memp *)memp_bases[i];
#endif							/* MEMP_SEPARATE_POOLS */
		/* create a linked list of memp elements */
		for (j = 0; j < memp_num[i]; ++j) {
			memp->next = memp_tab[i];
			memp_tab[i] = memp;
			memp = (struct memp *)(void *)((u8_t *)memp + MEMP_SIZE + memp_sizes[i]
#if MEMP_OVERFLOW_CHECK
										   + MEMP_SANITY_REGION_AFTER_ALIGNED
#endif
										  );
		}
	}
#if MEMP_OVERFLOW_CHECK
	memp_overflow_init();
	/* check everything a first time to see if it worked */
	memp_overflow_check_all();
#endif							/* MEMP_OVERFLOW_CHECK */
}

/**
 * Get an element from a specific pool.
 *
 * @param type the pool to get an element from
 *
 * the debug version has two more parameters:
 * @param file file name calling this function
 * @param line number of line where this function is called
 *
 * @return a pointer to the allocated memory or a NULL pointer on error
 */
void *
#if !MEMP_OVERFLOW_CHECK
memp_malloc(memp_t type)
#else
memp_malloc_fn(memp_t type, const char *file, const int line)
#endif
{
	struct memp *memp;
	SYS_ARCH_DECL_PROTECT(old_level);

	LWIP_ERROR("memp_malloc: type < MEMP_MAX", (type < MEMP_MAX), return NULL;);

	SYS_ARCH_PROTECT(old_level);
#if MEMP_OVERFLOW_CHECK >= 2
	memp_overflow_check_all();
#endif							/* MEMP_OVERFLOW_CHECK >= 2 */

	memp = memp_tab[type];

	if (memp != NULL) {
		memp_tab[type] = memp->next;
#if MEMP_OVERFLOW_CHECK
		memp->next = NULL;
		memp->file = file;
		memp->line = line;
#endif							/* MEMP_OVERFLOW_CHECK */
		MEMP_STATS_INC_USED(used, type);
		LWIP_ASSERT("memp_malloc: memp properly aligned", ((mem_ptr_t)memp % MEM_ALIGNMENT) == 0);
		memp = (struct memp *)(void *)((u8_t *)memp + MEMP_SIZE);
	} else {
		LWIP_DEBUGF(MEMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("memp_malloc: out of memory in pool %s\n", memp_desc[type]));
		MEMP_STATS_INC(err, type);
	}

	SYS_ARCH_UNPROTECT(old_level);

	return memp;
}

/**
 * Put an element back into its pool.
 *
 * @param type the pool where to put mem
 * @param mem the memp element to free
 */
void memp_free(memp_t type, void *mem)
{
	struct memp *memp;
	SYS_ARCH_DECL_PROTECT(old_level);

	if (mem == NULL) {
		return;
	}
	LWIP_ASSERT("memp_free: mem properly aligned", ((mem_ptr_t)mem % MEM_ALIGNMENT) == 0);

	memp = (struct memp *)(void *)((u8_t *)mem - MEMP_SIZE);

	SYS_ARCH_PROTECT(old_level);
#if MEMP_OVERFLOW_CHECK
#if MEMP_OVERFLOW_CHECK >= 2
	memp_overflow_check_all();
#else
	memp_overflow_check_element_overflow(memp, type);
	memp_overflow_check_element_underflow(memp, type);
#endif							/* MEMP_OVERFLOW_CHECK >= 2 */
#endif							/* MEMP_OVERFLOW_CHECK */

	MEMP_STATS_DEC(used, type);

	memp->next = memp_tab[type];
	memp_tab[type] = memp;

#if MEMP_SANITY_CHECK
	LWIP_ASSERT("memp sanity", memp_sanity());
#endif							/* MEMP_SANITY_CHECK */

	SYS_ARCH_UNPROTECT(old_level);
}

#endif							/* MEMP_MEM_MALLOC */
